SIST EN ISO 4037-2:2021

EN ISO 4037-2:2021 - Radiological protection: Dosimetry overview

EN ISO 4037-2:2021 (ISO 4037-2:2019) specifies dosimetry procedures for X‑ and gamma‑ray reference radiation used to calibrate dosemeters and dose‑rate meters and to determine instrument response versus photon energy. The standard covers radiation qualities in the energy ranges ≈8 keV to 1.3 MeV and 4 MeV to 9 MeV, for air kerma rates above 1 µGy/h, and addresses both free‑in‑air air kerma (Ka) and the ICRU/ICRU‑related phantom operational quantities (H*(10), Hp(10), H'(3), Hp(3), H'(0.07) and Hp(0.07)), including dose rates.

Key topics and technical requirements

• Scope and quantities: Procedures for determining air kerma free‑in‑air and converting to phantom‑related operational quantities used in radiation protection.
• Reference field production: Two approved methods (defined in ISO 4037‑1):
  • Matched reference fields - fields produced to closely follow nominal spectra so that recommended conversion coefficients (see ISO 4037‑3) can be applied; coefficients are given only for specified source‑to‑dosemeter distances (e.g., 1.0 m, 2.5 m).
  • Characterized reference fields - spectra or conversion coefficients established by spectrometry or by direct measurement with secondary standard dosimeters; applicable for any distance (provided air kerma ≥ 1 µGy/h).
• Validation & conversion: Procedures to validate spectral differences and determine or measure conversion coefficients from air kerma to operational quantities.
• Instrumentation and procedures: Guidance on use and calibration of standard instruments (ionization chambers), geometry, chamber support, corrections (temperature, pressure, recombination, leakage, beam non‑uniformity) and measurement of photon spectra.
• Uncertainty: Target overall expanded uncertainty (k = 2) of about 6 % to 10 % for phantom‑related operational quantities in reference fields. Component analysis and statement of uncertainty are detailed.
• Limitations: Not applicable to pulsed reference fields. Requires charged‑particle equilibrium in the reference field; energies where inherent equilibrium may not be established are noted (electron ranges for specific depths).

Practical applications and users

Who uses EN ISO 4037-2:

• Calibration laboratories and national metrology institutes
• Manufacturers of dosemeters and dose‑rate meters
• Radiation protection service providers and hospital physics departments
• Regulatory authorities and conformity assessment bodies
• Research groups validating detector energy response

Typical applications:

• Calibration and type‑testing of radiation protection instruments
• Establishing traceable reference fields for workplace monitoring
• Determining energy‑dependent response and conversion coefficients
• Supporting compliance with radiation protection regulations and quality assurance programs

Related standards and references

• ISO 4037‑1 - Methods for production of X and gamma reference radiation (used together with Part 2)
• ISO 4037‑3 - Conversion coefficients for use with matched reference fields (limited distances)
• ICRU operational quantity definitions and dosimetric conventions (referenced in EN ISO 4037‑2)

Keywords: EN ISO 4037-2:2021, ISO 4037-2, radiological protection, dosimetry, reference radiation, calibration, air kerma, H*(10), Hp(10), dosemeters, dose‑rate meters.